Process for cracking oils



Aug 9 1927 c. P. DuBBs PROCESS FOR CRACKING OILS original Filed Feb. 17. 1921 Inl lll.

e. ,a/e/z Carbon' Bub/bfi.

io the Patented A ug. 9,192.7.

UNITED STATES* PATENT OFFICE.

*CARBON P. noms, OF WILMETTE, ILLINOIs, AssIGNOR To UNIVERSAL OIL PRODUCTS,

COMPANILOP` CHICAGO, ILLINOIS, A CORPORATION or SOUTH DAKOTA.

PROCESS ron. CRACKING OILs.

Application led February 17, 1921, ASerial 110.445,871. Renewed March 24, 192-7.

This invention 'relates to a process `for cracking hydrocarbon oils and refers more particularly to an improved process whereby the apparatus may be operated continuously for a greater period of time due to the fact that the carbon accumulation is restricted to a portion of the apparatus which does not hinder the ow of oil in the system lor cause y'clogging or hot spots which so often attend continuous operationjof processes of this type. f j

Among the salient objects of the invention are to provide a process whereby the Oil during conversion is maintained in an enlarged l5 expansion chamber and the greater part of the carbon deposition which .takes place during the cracking oi? the oil, is restricted to a collection upon vaporization the expansion chamber, keeping v the carbon separate from the outside `heated surfaceof the retort away from the inlet and outlet lines communicating therewith; to provide an apparatus which is easily cleaned and one which is particularly designed for collecting the deposited carbon in the above described manner.

The figure is a 'side elevation partly in -section with parts broken away to more clearly show the details of the apparatus.

Referring to the drawings, the raw oil is introduced to thetop of the dephlegmator 1 through aninlet pipe 2 controlled by 'a` valve 3. The oil travelling down through 'the dephlegmator serves to separate the higher boiling point fractions from the oil vapors, which travel up through the dephlegmator in an opposed direction. The raw o1l with its condensate contentA which itv acquires in .the dephlegmatory collects in the bottom and is drawn off through a line 4 and is'directed tothe shell still 5 which is mounted above the furnace v6. At the elbow in the line 4 is.

l inserted a pyrometer 7 for the purpose of ascertaining the temperatureof the oil a-.t

still and being heated to a temperature at that point..l TheV still 5 has the/detachable which conversion takes place the vapors re-y I leased. will-rise through the vapor line 11 and after being dephle0fmated b the raw oil I pyromter 1'3 is interposed and to a water condenser 14, thence through. the line 15 to a receiver 16. The receiver is fitted with the liquid level gauge -17 pressurerelief pipe 18 draw-offV line 22 controlledbly a' valve 23. A

` residuum line 24 controlled by 'a valve 25 1s tapped into `the still shell directly above the lower end ofthe collector plate9.

, Withthe conversion of the oil in the shell `c ontrolled'by a valve 19 and liquid draw-oli' 2Q regulated by a valve 21 and a secondary still, there is a substantial separation of free carbon which is usually permitted to collect in thebottom of the st1ll Where. it causes dilculties due to thefactthat it insulates the oil from the heat of the furnace, causing hot s ots and often necessitatingv the shutting' own of the apparatus or .hindering the 'operation ofthe process due to the clogging of heating tubes, draw-oil lines orl other plpes communicating with the .expansion chamber. The collection plate ositioned in the interior of the shellsti l, as

shown, affords a collectin surface for this 'free carbon and keepst e carbon atall times isolated from Contact with the outer surface of the still. Inaddition 'to this feature, the carbon is preventedfrom collecting inthe bottom of the stillfwhere it vobstructs vfree circulation of the oil, reducing the elciency of the process'and lessening the residuum line, it is possible to accumulate the'greater portion of `the precipitated carbon on the surface of this collector late im the amountl of conversion taking place in the l ecting sur' andl Hush thes'ame with the heavy residual.4 'y

oil through the residuum line from time to time. The positioning of this plate above the inlet line also serves as 'abaille forfthe incoming oil to be treated and causesthe same to ytravel along the bottom surface of thestill where it is subjected to the highest temperature. After travelling the length of the still and being subjectedconstantly to a cracking temperature the crac-kedoil will pass around the end of the collector plate in a direction shownv by the arrow and liow` over the top of the collecting surface where there is expansion surfacejaorded for the bon is released in* this vaporization will be deposited on the collector plate and will flow oft' through the residuum line with the residual oil. The still can be easily cleaned by removing either or both of the plates bolted to the ends thereof.

Primarily, it is the temperature to which the oil is heated in the pressure still which governs the percent of that oil .which is cracked and this in turn governs the amount .of free carbon produced. Keeping the production of carbon down to a certain -limit overcomes any substantial amount of carbon settling out of the oil, but leaves practically all of the carbon fluctuating in the oil and in this state it may be continuously carried out of the portion of the apparatusv where the conversion of the oiltakes place. The proportion of the oil cracked along with more or less of the uncracked oil is separated by being vaporized, the uncracked portion being refluxed to the heating zone -free from any free carbon therein. It will be recognized that by placing a partition or collecting plate in the lower section of the still in such a manner that when reflux and raw oil is'fed in below where the heat is applied, thence continuously flowing to theuppersection of the still not in direct contact with the heat of the furnace that there the substantial portion of the conversion will take place. In the upper portlon of the' still above the partition the oil is 'vaporized and the residuum with more Vor less of the carbon flows down the'top of the partition and is drawn off through the residuum line. This operation is continued until the upper portion of the still becomes filledA with carbon 'at which time -it may be shut 'down and cleaned.

This apparatus, in addition to other\ad .vantages, 1s economical in fuel combustion as the oil will not have `to be heated to as high a temperature to do the same amount of cracking due to thefa'ct that the'carbon is notv permitted tol collect in the bottom of the still and there insulate the oil from the heat of the furnace. The simplicity of the apparatus and the advantages which it presents in the way of increased heat and ecoonmical operation make it very, desirable from many viewpoints.

In positioning the collector platein the still' it is not essential""that the plate be inclined as a horizontal plate will supply the same collecting surface and permit the same amount of vaporization as an inclined plate.

-It is true that the inclination slightl assists in drawino off the residuum but thls ydetail is not vita Another' feature of im ortance is the length 4of the upturned en of the collector plate.- VIf this `upturned portion extends practically to orpnear the surface of the oil' 1n the still or vaporizng chamber, the-heavy residuum and precipitated carbon will be prevented from backing up into the bottom of the still; also a lower level may be maintained in the vaporizing portion of the still which would reduce materially the amount of oil'maintained at one time therein. By this constructionthere is maintained at all times a solid body of reflux and raw oil in the lower portion of the still or that portion to which the greatest amount of heat is subjected. This oil as it rises in a column at the end of the chamber adjacent the upturned extension of the collector plate overflows into the -vaporizing portion of the still and the,

conversion or vaporiz'ati'on taking place in that portion will restrict the greater part or substantially all of the carbon deposition to the surface of the collector plate.

I claim as my invention 1. A process for cracking hydrocarbon oil, consisting in converting the oil at a cracking temperature in a reacting chamber, dephlegmating and condensing the generated oil vapors, returning the refiux and causing it to be introduced and flow through the zone of highest temperature in said re'- acting chamber, circulating the oil to promote conversion in the upper part of sai-d chamber and collecting the recipitated carbon in the interior of the c amber and out of contact with the lower heated portion thereof.

2. A process for cracking hydrocarbon' mote conversion in the upper part of said chamber and collecting the' precipitated carbon in the interior o f the chamber and out of contact withithe lower heated shell .portion'of said chamber and drawingofl the residual substance.

3. A process f for cracking hydrocarbon oil consisting in converting the oil at a cracking temperature in apartitioned reactin chamber, charging the oil to the. portion su jected to the highest temperature, circulatingr the heated oil to a vaporizing portion, ephlegmating and condensing the generated vapors, collecting the preci itated carbon out of contact with the lower eated ortion of said reactin chamber and drawingof the residual su stance with substan-l tial (iantities of said precipitated carbon.

4. process of cracking petroleum oil, comprisin introducing oil to a converting chamber, 1n causing the oil introduced '5to said chamber to pass lengthwise thereof be- `neath a horizontal-baille, andthenaround said baille to the upper portion ofthe ch ber, in collecting on said baille carbon 13| precipitated during va orization of the oil without allowing sai carbon to contact with the heated wall of the conversion chamber, in withdrawing-'said carbon accumulating on said baille, in discharging vapors from said conversion chamber lto a dephlegmator, and in delivering reflux condensate travel lengthwise thereof beneath a baille.

and then into the upper portion of thestill to be subjected during a long .course of travel to the maximum heating temperature, in collecting on said baille precipitatedl carbon 'and'heavy residue resulting from the cracking of the oil without allowing said residue, to deposit upon the heated walls of the still and to revent it from mixinv with the charginV oi, in withdrawing said residue accumu ating on the baiiie, and in continuouslv'introducing raw oil to the still beneath the baille.

CARBON P.V DUBBS. 

